Suspension systems are the systems configured to suspend a vehicle chassis above its wheels, to maintain good grip on the road while isolating the vehicle systems from road shocks and impacts. These can be contradicting demands that require compromising. Commonly used suspension systems, either rear or front, include: springs, shock absorbers and the linkages between to the vehicle's chassis and the wheels, all of which are external to the wheels.
In-wheel suspension systems have several advantages as well as challenges that must be overcome. Such suspension systems can reduce the weight of the vehicle and allow flexible damping of each wheel separately. There are several examples of in-wheel suspension systems which require complicated connections to the vehicles' chassis or the use of an expensive electrical suspension system in connection to an electrical motor. Such systems cannot be implemented to every vehicle.
The Watt's linkage (also known as the parallel linkage) is a well-known mechanical linkage made from three arms, in a “Z” like shape configuration, in which a central moving point of the central arm is configured to move in a substantially straight line. Such a mechanism can be used in vehicles suspension systems, allowing an axle of a vehicle to travel vertically while preventing sideways motion. When used in a vehicle suspension system, the Watt's linkage is assembled external to the wheel.
Never before has there been an attempt to combine the Watt's linkage in an in-wheel suspension system, such that the entire Watt's linkage is located in the inner rim of the wheel.